JPH0733424Y2 - Corona discharger - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corona discharger in which a discharge electrode is attached to a shield case having an opening on the discharge side through an insulator.

[0002]

2. Description of the Related Art In electronic blasting machines, printers, facsimiles and the like, as a means for charging, transferring or discharging a photosensitive member, a wire-shaped discharge electrode and one direction surrounding the electrode and discharging the electric charge are opened. A corona discharger consisting of a shield case is used exclusively. Generally, the corona current generated by the charger consisting of the discharge electrode and the shield case is due to the ripple of the high-voltage power supply that feeds the discharge electrode, the mechanical specifications of the discharge electrode, the shield case, and the control grid used as necessary. , Fine irregularities, and other irregular high frequency components based on various factors are included. This high-frequency component becomes radiant noise, which affects external electronic devices and the like. Therefore, today's standards impose limits on this radiant noise.

Conventionally, in order to control the radiant noise emitted from the corona discharger, a high voltage transformer is shielded, and a high voltage output line connected from the high voltage transformer to the corona discharger has a ring shape for a noise filter. I was trying to solve everything on the power supply side, such as installing the core.

[0004]

However, the above method is not effective because the noise is removed at a place distant from the noise generation source, and the cause of the noise generation is extremely complicated as described above. Therefore, there is a problem that the countermeasure cannot be ad hoc because the accurate evaluation cannot be performed in the design stage.

An object of the present invention is to provide a corona discharger capable of effectively reducing noise by directly connecting a capacitor to a discharge electrode which is a noise generating source.

[0006]

According to the present invention, a capacitor of several pF to several hundred pF is mounted between the shield case and one end of a discharge electrode mounted via an insulator in a shield case having an opening on the discharge side. It is characterized by

[0007]

Since the discharge electrode is a noise source, noise can be effectively removed by directly connecting a high-frequency removing capacitor to the discharge electrode.

[0008]

FIG. 1 shows an embodiment of the present invention. The shield case 1 has a U-shaped cross section, and the discharge electrode 2 is provided inside the shield case 1.
A corona discharger is constructed by fixing both ends of the insulator to the insulators 3 and 4. A spring 5 is provided on the power receiving side of the discharge electrode 2 to prevent the discharge electrode from loosening. A high voltage output line (not shown) is connected to the power supply side,
Further, a high voltage transformer (not shown) is connected to the high voltage output line. The capacitor 6 has a capacitance of several pF to several 100 pF, and is connected to the non-power supply side terminal of the discharge electrode 2 and the shield case 1.
Is connected in between.

FIGS. 2, 3 and 4 and 5 are views showing corona current waveforms when the load of the corona discharger is changed and when the capacitor is not connected and when the capacitor is connected. 2 and 4 show the case without a capacitor, and FIGS. 3 and 5 show the case with a capacitor. Also, FIGS.
Shows the noise waveform when there is no capacitor and when there is a capacitor. N1 indicates a static noise waveform when no voltage is applied to the corona discharger, N1
Reference numeral 2 shows a noise waveform when a high voltage power supply is applied. Noise N2 due to the frequency band of A in the figure is the noise radiated by the corona discharger. From FIGS. 2 to 5,
It can be seen that the high frequency noise riding on the corona current wave type is reduced by connecting the capacitor 6, and the absolute amount of noise emitted by the corona discharger is extremely increased by connecting the capacitor 6 from FIGS. 6 and 7. You can see that it is decreasing.

As shown in FIG. 1, the capacitor 6 is connected between the non-feed side terminal of the discharge electrode 2 and the shield case 1 to obtain a better result than the connection between the feed side terminal and the shield 1. I was able to. However, a significant noise reduction effect can be obtained at either terminal, compared to the case where no capacitor is connected.

[0011]

According to the present invention, since a capacitor that directly acts on the discharge electrode which is the source of noise is connected, a very remarkable noise reduction effect can be obtained.
Further, unlike the conventional case, it is not necessary to provide a complicated noise reducing means on the power source side.

[Brief description of drawings]

FIG. 1 is a block diagram of a corona discharger according to an embodiment of the present invention.

[Figure 2]

FIG. 5 is a diagram showing corona discharge current waveforms of a conventional corona discharger without a capacitor and a corona discharger of the embodiment.

FIG. 6,

FIG. 7 is a diagram showing noise waveforms of the conventional corona discharger and the corona discharger of the embodiment.

[Explanation of symbols]

 1-Shield case 2-Discharge electrode 6-Capacitor

Claims (1)

[Scope of utility model registration request] 1. A corona discharger in which a capacitor of several pF to several hundreds pF is mounted between one end of a discharge electrode mounted via an insulator in a shield case having an opening on the discharge side and the shield case. .